a. Field of the Invention
The invention relates generally to a lamp device. More particularly, the invention is directed to a lamp device capable of projecting image patterns with gradients.
b. Description of the Related Art
In order to provide an image pattern generated by a puddle lamp with gradients, a conventional method is to perform halftone processing on the pattern through the use of dots, varying either in size or in spacing, to cause variations on brightness. However, large dots are liable to form undesired apparent images, and small dots are liable to cause Moiré patterns due to their regular arrangement. Therefore, gradient effects and visual effects may be lowered. Besides, although the use of small dots may prevent the formation of apparent dot images, a great number of small dots with high DPI are needed to provide low grayscale (low brightness) effects to result in a bulky figure file, time-consuming image processing and higher costs. Further, in the conventional design, a halftone pattern and a profile pattern are formed on the same layer, and thus it may cause a serrated edge of a projected image pattern to thus worsen visual effects, with the serrated edge being formed by dots images besides a pattern profile. Moreover, in case a profile pattern and a gradient pattern are formed on the same layer by the lithography printing, a line width that can be printed out is restricted to be larger than a minimum value to result in thicker profile lines (≥2 mm) and thus fails to further improve image resolution.